Active Directory® Domains and Trusts is the Microsoft Management Console (MMC) snap-in that you can use to administer domain trusts, domain and forest functional levels, and user principal name (UPN) suffixes.

• Managing Domains and Forests
  
  
• Managing Trusts
  
  
• Managing Forest Trusts
  
  
• Troubleshooting Active Directory Domains and Trusts
  
  
• Resources for Active Directory Domains and Trusts
  
  
• User Interface: Active Directory Domains and Trusts